Mechanical movement



Sept 28, 1954 G. E. BJRKLUND ET AL 2,690,081

u MECHANICAL MOVEMENT Filed Aug. 3, 1950 3 Sheets-Sheet l Sept. 28, 1954Q E BJRKLUND ET AL 2,690,081

MECHANICAL MOVEMENT 5 Sheets-Sheet 2 Filed Aug. 3, 1950 Sept' 28, 1954G. E. BJRKLUND ET L 2,690,081

MECHANICAL MOVEMENT 5 Sheets-Sheet 5 Filed Aug. I5, 1950 Patented Sept.28, 1954 2,690,081 MECHANICAL MOVEMENT Gustaf Erik Bjrklund and Karl keLindbloni, Stockholm, Sweden, assignors to Aktiebolaget Dentatus,Hagersten, Sweden, a corporation ,of

Sweden Application August 3, 1950, Serial No. 175,396

Claims priority, application Sweden August 23, V1949 `11 Claims. l

The present invention refers to a handtool have ing a rotating part anda part moving .back and forth, the latter part being intended to carry aworking tool and receiving its motion from the rotating part through acrank mechanism.

' One object of the invention is to provide Aa handtool of this kind inwhich the length of the stroke of the part moving back and forth can bevaried by changing the eccentricity of the `crank pin. In a preferredform of the invention the crank pin is adjustably arranged on therotating part in such a way that, when the crank pin is adjusted inorder to change the length of the stroke, a counterweight, arranged onthe rotating part, is automatically adjusted in such manner that thecrank mechanism remains balanced at every length `of the stroke. Ofcourse, the counterweight does not need to be shaped as a separateelement but may consist of a flywheel mass forming an integral portionof an engine part included in the rotating part.

Another object of the invention is to provide a handtool of the kindreferred to in which the part moving back and forth is arranged to beturned about its axis. Suitably, vthe said part `is arranged to beturned by hand by means offwhich the working tool may be guided so thatit closely follows the curvature of the object worked upon. In addition,the part may be arranged to revolve freely, so that, in case of a planeworking tool being used, this may automatically adjust itself into theWorking plane by being guided by the surface of the object. Further, theyhandtool may be arranged in such a way that the part mOYiIlS back andforth will be mechanically guidedin any angular position.

4Another object of the invention is to provide a handtool of the kindreferred to in which the working tool is prevented from being damaged,should it meet a resistance greater than normal.

Finally, an object of the invention is to provide a handtool of the kindreferred to .which is particularly easy to handle and handy to work withand therefore Will be suited for a great variety of uses in dilferentways, especially invling and grinding Work on objects of complicated andvarying shape.

Further objects and advantages of the invention will be apparent fromthe following description in connection with the accompanying drawingsin which: e

Fig. 1 is a'verticalsectional view of aform of handtool embodying theinvention,

Fig. 2 isa horizontal sectionalview ltaken on the line II-II of Fig. 1,

Fig. 3 is a vertical fragmentary sectional view of .thehahdt991erdint``g$- 1 and 2 applied to anspecial use,`

Fig. 4 is atop plan view of the handtool shown inFig's c.

Fig. 5 is ,a vertical fragmentary sectional View of a modied forinof thehandtool according to Figs-land?! Fig. o is a crosssectional View takenon the line VI-VI of Fig. 5a'nd` Fig. "1 is a side elevation showing howthe handtool is held .inoperation I n theflg'ures, YI indicates the axleneck or the connecting partthrough .Whichthe tool is coupled to asuitabledriving arrangement, for instance a flexible ,shaftdriven.b5I,anelectric motor. The axle neck is" carried out as an integral pieceoff a slide holder 5, `ironrnalled in thev casing 4 of the4 handtool bymeans of ball bearings 2 and 3.

Eccentrically in thefs'lide' holder', fa revolving slide 6 iscarri'edwhichlcan'be locked in any optional angular position thIOllgl a lockingvscrew` `l, threaded in theslide holder.'y Therevolving slide isprovided with anaxiallbore, eccentrically positioned, in which a bushing9, serving as a bearing for a crank v.pi1'1 f,8, yis threaded. At thetop, the bore has' an' enlarged portion or cavity I0, serving thedoublefpurpseof partly effecting the balancing vand partly effecting thelubrication by forming Aa reservoir for lubricating oil. I n order .to`facil.itatthe 'turning of the slide. its upper portion has la largediameter so as to reach the lnearestfedge ofthe slide holder, and theSlide holder is vprovided AWitha cylindrical cavity, subst antiallyfilled 4by the abOVe-men.- tioned upper portion of the slide. lOnaccount of the cavity," 'an edge liange `Il is formed on one side of the,slide holder, the shape o f said fiangebeingobvious rfronlig. 2,. Theupper free space of the casing] contains thecrank mechanism which,besides the crank pin, consists ,of a connectingl rod l2, connected with.a toolholder i3 by `means of a hall'and socket joint. The holdertravels ,in abushing M, threaded inthe casing,.and is locked throughacheck nut I5. The space containing the crank mechanism is covered byacap 16," theedge 'portion of which extends intofthe casingandisprovidedwth an opening I1 through {whichthe connecting rod passes. Thehead |08 `of the connectingV rod is firmly connectedwiththe Vcrank pinby means of a peg I9 nassiegihrough these Peris! ,The @POF site endofthe connectingrod is provided with a head zandrassesthrough a ball llwhich is located'nvoneendv-of the here of thetube shaped tool holder andrests against a spherical thrust surface, formed therein. At theopposite end of the tool holder, a tool socket 22 is firmly connectedwith the holder and projects partly in the bore thereof. A helicalspring 23 is arranged between the socket 22 and the head 20 of theconnecting rod and presses the head against the ball 2| which is thussecured between the head and the spherical thrust surface. 'Ihe socket22 is provided with a central bore 24 in which a tool may be introducedand secured by means of a clamping screw 25.

It is clear from the construction that the tool holder i3 receives arectilinear motion back and forth in the bushing I4 and is free to turnabout its own centre axis. Therefore, a le arranged in the socket willadjust itself in the working plane. When working in a definite plane,the tool holder may, however, be guided so as to retain perpetually acertain angular yposition during its motion back and forth. For thispurpose, a guiding slide 26 is displaceably and rotatably arranged onthe bushing I4. The guiding slide has a longitudinal slot 2l in which aprojection 28 on the tool socket, in which the clamping screw 25 isthreaded, may travel, the guiding slide having been displaced forwardlyfrom its rear position to the guiding position, as shown in Figs. 1 and2. The guiding slide is locked by means of a clamping screw 29.

If the working tool should meet a resistance greater than normal duringits motion back and forth, the spring 23 will be compressed, so that themovement of the tool is limited. By this means, the working tool isprevented from being subjected to strains which would otherwise damagethe same.

As the crank pin 8 is firmly connected with the head of the connectingrod and journalled in the slide 6, large bearing surfaces can beattained, without any particular space being required therefore. Thelubricating oil existing in the cavity I is supplied to the bearingsurface of the crank pin through openings 30 in the bushing 9. As theslide rotates, the oil is thrown outwardly against the side walls of thecavity and is thus prevented from being sucked into the bearingclearance in too large a quantity through the capillary force and afterthat being thrown away because of the centrifugal force.

The crank pin 8 being eccentrically arranged in the slide 0, which inits turn is eccentrically located in the slide holder, the eccentricityof the rank pin i. e. its distance from the centre of rotation can bevaried by turning the slide. On account of the cavity I 0, the slidewill have an eccentrically positioned mass equivalent to a certaincounterweight which, as the slide is turned, is automatically adjustedin Such a way that its moment of inertia in respect of the axis ofrotation is perpetually counterbalancing the moment of inertia of therotating parts of the crank mechanism in respect of the same axis. 'Ihatthis is the case can be understood more easily from the fact that theweight of the material removed on account of the cavity is the same asthe weight of the rotating parts of the crank mechanism and that thecentre of the cavity lies at the same distance from the axis of rotationas said parts.

By means of an arrangement shown in Figs. 3 and 4, the describedhandtool may be made to give to the working tool a rotating motion aswell as the motion back and forth. For this purpose, the

crank pin is provided at the top with a pivot 3l" on which one end of abar` 32 is journalled, a

working tool, `for instance in the form of a grinding disk 33 beingattached to the other end. The grinding disk is carried by the ballshaped end 35% of a pin 35 fastened to the bar and is thus capable ofadjusting itself freely into the working plane. The guiding slide 26 isput in the guiding position, having been turned through degrees from theposition shown in Fig. l, so that the slot 2l is directed upwardly andguides the projection 28 in vertica-l position. The bar 32 is carriedthrough a transverse bore 36 in the clamping screw 25 and the cap I6 isturned through 180 degrees, so that an opening 3l is put into a positionin which the bar is a'ble to pass freely through the wall of the cap.

As the crank pin rotates, the bar will oscillate about the centre axisof the clamping screw 25 and follows in the main the back and forthmotion of the tool holder, so that it will be displaced in the bore ofthe clamping screw only to a small degree. The working tool thus carriesout a circular motion in the working plane.

In Figs. 5 and 6 the part of the handtool moving back and forth consistsof a tool holder |0I and a slide |02 connected therewith which travelsin a cylinder |03. In the central bore of the tool holder a working toolcan be introduced and locked by means of a locking screw |04, which isthreaded in a projecting portion |05 of the tool holder. The part movingback and forth receives its motion from a rotating part |00, of the sameconstruction as that shown in Fig. '1, through a crank mechanism,consisting of a connecting rod |01 and a crank pin |08, arranged on therotating part. One end of the connecting rod is pivoted on the crankpin, the other end being connected with the slide through a universalcoupling yielding in the longitudinal direction of the slide. Thecoupling is formed by an element |09 provided with a spherical surfacewhich rests against a corresponding spherical bottom surface in acentral bore of the slide, and a helical spring H0 located in saidboring through which a head or flange II2, formed in the end of theconnecting rod, is jammed between a piston I|| and the element |09. Inorder to facilitate the turning of the slide, the head I I2 is providedwith a central point which rests against the plane surface of the pistonI The cylinder |03 is threaded in the casing II3 of the handtool in sucha manner that its centre line forms right angles with the axis of therotating part and is located in the plane of motion of the crankmechanism. The cylinder is held in a fixed position by means of alocking nut I4. On the outside of the cylinder a revolving slide I i5 isjournalled which is widened at its forward end and extends forwardlyaround the tool holder, the projecting portion |05 of which travels in alongitudinal slot I I6 in the widened portion of the revolving slide.The revolving slide is prevented being displaced in axial direction byits journal portion being located between the locking nut I I4 and anedge lla-nge I'I in the forward end of the cylinder.

In order to make the turning of the revolving slide possible during thework, a control part I I8 is arranged on the revolving slide. Thecontrol part has a cylindrical bore through which the revolving slide iscarried, and a cut slit IIS extending from the bore, by means of whichit can be clamped on the revolving slide by tightening clamping screw|20, the lengthened portion of which serves as a handle I2I. Oppositethis handle on the other side of the control part, a

similar handle |22 is arranged coa-'xially in rela tion to the firstmentioned handle. The control part may thus be locked in anyoptionalangular position relative to the revolving slide and may be displacedaxially thereon in released condition. When the control part is placednear the locking nut i |4, it may beheld in a xed angular position bymeans of a peg |23, driven home into the casing H3, which entersa `slot|24 of they lar position which is determined by the surface worked upon,as the plane tool is carried against and guided by this. Thus theworking tool will adjust itself automatically.

If, on the other hand, the control part is clamped on to the revolvingslide in such a position that the peg |23 is not located in the slot|24, it will be possible to vary the angular position of the revolvingslide by hand during operation and thus also that of the tool holder byactuating the handles |2| and |22. The handtool is then held in the handin the manner seen in Fig. '7, the index ringer being held on the handle|2| and the middle ringer on the handle |22. The control part may bedisplaced axially on the revolving slide and be clamped in a positionsuitable in each individual case,` for the length of the fingers.

The handtool described and shown in the drawings is only to beconsidered as an example and may be varied in many different ways withinthe limits stated by the following claims.

What I claim is:

1. A hand tool comprising a casing, a tool holding member mounted forreciprocation in said casing, an axle mounted for rotation in said casing on an axis transverse to the direction of reciprocation, a crank pinmounted on said axle for movement toward and away from the axis theerof,a connecting rod operatively connecting said pin and said reciprocatingtool holding member, and means operatively connected to said eccentricpin for maintaining a counterbalanced condition of said pin and saidtool in different positions of said pin.

2. A hand tool comprising a casing, a slide holder mounted on saidcasing for rotation about a rst axis, a slide journaled in said slideholder on a second axis eccentric to said rst axis, a crank pin mountedin said slide holder on a third axis eccentric to said second axis,means to retain said slide in an adjusted position relative to saidslide holder, a tool holder mounted for reciprocation in said casing ina direction transverse to said rst axis, a connecting rod having one endconnected to said crank pin and the other end connected to said toolholder, said slide having a cavity corresponding to the weight of theunbalanced rotating parts.

3. A hand tool comprising a casing, a slide holder mounted on saidcasing for rotation about a first axis, a slide journalled in said slideholder on a second axis eccentric to said first axis, a crank pinmounted in said slide holder on a third axis eccentric to said secondaxis, means 6 to retain said slide in an adjusted position rela-f` tiveto said slide holder, a tool holder mounted for reciprocation in saidcasing in a direction transverse to said rst axis, a connecting rodhaving one end connected to said crank pin and the other end connectedto said tool holder, said slide having a cavity coresponding to theweight of the unbalanced rotating parts, said cavity being incommunication with the bearing Surfaces of said crank pin for supplyinglubrication thereto. Y

4. A hand tool comprising a casing, a slide holder mounted on saidcasing for rotation about a rst axis, a slide journalled in said slideholder on a second axis eccentric to said first axis, a crank pinmounted in said slide holder on a third axis eccentric to said secondaxis, means to retain said slide in an adjusted position relative tosaid slide holder, a tool holder mounted for reciprocation and rotationin said casing in a direction transverse to said first axis, aconnecting rod having one end connected to said crank pin and aspherical connection between the opposite end of said connecting rod andsaid tool holder whereby said tool holder may rotate relative to saidconnecting rod and said connecting rod may oscillate relative to saidtool holder.

5. A handtool comprising a casing, a slide holder mounted on said casingfor rotation about a first axis, a slide journalled in said slide holderon a second axis eccentric to said first axis, a crank pin mounted insaid slide holder on a third'axis eccentric to said second axis, meansto retain said slide in an adjusted position relative to said slideholder, a tool holder mounted for reciprocation in said casing in adirection transverse to said first axis, a connecting rodv having oneend connected to said crank pin, the other end of said connecting rodbeing slidably connected to said tool holder through a swivel jointwhereby a tool holder may rotate relative to said connecting rod, andyieldable means in said tool holder for opposing sliding movement ofsaid connecting rod relative to said tool holder, whereby saidconnecting rod will positively move said tool holder in one directionand yieldably move the same in the opposite direction.

6. A handtool comprising a casing, a slide holder rotatably mounted insaid casing on a first axis, a slide rotatably mounted in said slideholder on a second axis eccentric to the said first axis, a bore in saidslide having its axis eccentric to said second axis, a bushing mountedin said bore, a crank pin rotatably mounted in said bushing, a toolholder mounted for reciprocation and rotation in said casing, aconnecting rod extending between said crank pin and said tool holder forcausing reciprocation of said tool holder, said slide being providedwith a lubricant retaining and balancing recess surrounding saidbushing, said bushing being provided with passages in communication withsaid recess and the crank pin for the passage of lubricant to thelatter.

7. A hand tool comprising a casing, a slide holder mounted on saidcasing for rotation about a first axis, a slide journalled in said slideholder on a second axis eccentric to said rst axis, a crank pin mountedin said slide holder on a third axis eccentric to said second axis,means to retain said slide in an adjusted position relative to saidslide holder, a tool holder mounted for reciprocation and rotation insaid casing in a direction transverse to said rst axis, a connecting rodhaving one end mounted on said crank pin, said tool holder having abore, a spring positioned in said bore, the other end of said connectingrod extending into said bore, and engageable with said spring, means toretain said other end of said connecting rod in said bore whereby saidtool holder is moved yieldably in one direction and positively in theother direction.

8. A hand tool comprising a casing, a crank mounted for rotation in saidcasing, a tool holder guide extending from said casing in a direction.

able crank mounted for rotation about an axis' in said casing, a bushingextending transversely to said axis, a tool holder mounted forreciprocation and rotation in said bushing, a guiding slide mounted forsliding movement and rotation about said bushing, said guiding slidehaving a slot formed therein, means for rotating said guiding slide,said tool holder having a projection extendable into said slot, meansconnecting said crank and said tool holder for reciprocating the latter,and means to secure a tool in said tool holder.

l0. A handtool comprising a casing, a counterbalanced crank mounted forrotation in said casing, a Atool holder mounted for reciprocating in adirection transverse to said crank, an outwardly extending guide mountedon said tool holder, means connecting said crank and tool holder forcausing reciprocation of said tool holder, an elongated bar slidablymounted in said outwardly extending guide and having one end pivotallymounted on said crank and the other end projecting outwardly from saidcasing, and means for supporting a tool at the outer end of saidelongated bar.

11. A handtool comprising a casing, an automatically counterbalancedadjustable crank rotatably mounted in said casing, a tool holder mountedin said casing for reciprocation in a direction transverse to saidcrank, a connecting rod extending from said crank to said tool holderfor reciprocating the latter, a bore in said tool holder, a compressionspring in said bore, a member having a spherical surface positioned insaid bore between said spring and the end of said tool holder adjacentthe crank, said tool holder including a surface coacting With saidspherical member permitting swivelling movement of said tool holder andconnecting rod, said spring normally urging said spherical surfacedmember into contact with the adjacent end of the tool holder.

References Cited in the rile of this patent UNITED STATES PATENTS NumberName Date 811,426 Mitchell Jan. 30, 1906 1,813,087 Sandage July 7, 19312,274,448 Hoover Feb. 24, 1942 2,331,760 Bitner Oct. 12, 1943 2,503,907Heer Apr. 11, 1950 2,524,207 Palmer Oct. 3, 1950 2,526,976 Smith Oct.24, 1950 2,561,344 Cutler July 24, 1951

